Content caching in small cells with optimized uplink and caching power

Traditional wireless networks mainly rely on macro cell deployments, meanwhile with the advances in forth generation networks, the recent architectures of LTE and LTE-A support Heterogeneous Networks (HetNets) that employ a mix of macro and small cells. Small cells aim at increasing coverage and capacity. Coverage both at cell edges and indoor environments can be significantly improved by relays and small cells. Capacity is inherently limited because of the limited spectrum, and although 4G wireless networks have been able to provide a considerable amount of increase in capacity, it has always been challenging to keep up with the growing user demands. In particular, the high volume of traffic resulting from video uploads or downloads is the major reason for the ever growing user demand. In the Internet, content caching at locations closer to the users have been a successful approach to enhance resource utilization. Very recently, content caching within the wireless network has been considered for 4G networks. In this paper, we propose an Integer Linear Programming (ILP)-based energy-efficient content placement approach for small cells. The proposed model, namely minimize Uplink Power and Caching Power (minUPCA), jointly minimizes uplink and caching powers. We compare the performance of minUPCA with a scheme that only aims to minimize uplink power. Our results show that minUPCA provides a compromise between the uplink energy budget of the User Equipment (UE) and the caching energy budget of the Small Cell Base Station (SCBS).